Empyema Symptoms, Causes, and Treatment

An empyema is a collection of pus in the pleural space, which is the area between the membranes that line the lungs. This condition is also sometimes called apylothorax, pleural infection, purulent pleuritis, or empyema thoracis.

It often occurs as a complication of pneumonia, and it can occur after a thoracentesis, lung surgery, with a lung abscess, or following chest trauma.

It is most commonly caused by infections with Streptoccocus or Staphylococcus bacteria. Symptoms may include a fever and chills, chest pain, a cough, and/or shortness of breath.

The diagnosis may be made with a chest X-ray or chest CT scan, and a thoracentesis (a needle is used to collect pleural fluid) may be done to identify the type of bacteria causing the infection. Treatment includes a combination of antibiotic therapy to treat the infection and chest tube placement to drain the fluid, though surgery may be needed to remove scar tissue and parts of the pleura (the membrane tissue) involved in the infection.

Anatomy

The pleural space lies between the visceral pleura (the membrane on the outside of the lungs) and the parietal pleura (the membrane lining the inside of the chest wall).

Ordinarily, this area contains the equivalent of a few teaspoons of pleural fluid. Normal pleural fluid is thin and translucent. Empyema fluid has a cloudy and thick appearance.

• When there is extra fluid in the pleural space it is referred to as a pleural effusion.
• With an empyema, this area may contain a pint or more of infected, pus-like purulent pleural fluid.

Empyema Fluid

The fluid in an empyema contains a combination of bacteria, dead cells, and white blood cells. The most common bacteria causing empyema are Streptococcus pneumoniae (the bacteria that causes pneumonia) and Staphylococcus aureus.

Signs and Symptoms

Signs and symptoms of empyema are caused by the infection and by the pressure on the lungs and chest from the increase of fluid in the pleural space.

Common signs and symptoms include:

• Fever and chills
• Night sweats
• Chest pain, often sharp and worsening with inspiration
• Shortness of breath
• A dry cough
• A productive cough if there's associated pneumonia
  
• Decreased appetite
• Fatigue
• A general sense of not being well

Sometimes irritation of the diaphragm and the phrenic nerve in this region from the build-up of fluid can result in hiccups. 

Causes

There are a number of different conditions that can cause an empyema to develop.

Some of these include:

• Pneumonia is the most common cause of empyema,
• Chest trauma, from a fall, motor vehicle accident, or another injury can contaminate the pleural space.
• Chest surgery, such as surgery for lung cancer or heart disease can puncture the pleura.
• A thoracentesis or a chest tube placement involves a small incision into the pleura.
• A bronchopleural fistula is a canal that may develop between the pleural space and the bronchi, allowing bacteria to pass from the bronchi to the pleural space. It most commonly develops with severe, necrotizing pneumonia.
• An infection in the abdomen (peritonitis) or area between the lungs (mediastinum) may spread into the pleural space,
• A lung abscess may rupture into the pleural space.

Risk Factors

Empyema is more likely to occur in someone who has one or more of the following conditions

• Diabetes
• A history of alcoholism
• Autoimmune diseases such as rheumatoid arthritis
• A suppressed immune system, such as with chemotherapy
• Lung diseases such as COPD and chronic bronchitis
• Gastroesophageal reflux disease

That said, these risk factors do not need to be present for an empyema to form.

Diagnosis

Your medical history can help identify whether you have risk factors for developing an empyema. If you have empyema, you may have diminished breath sounds on your physical examination.

Imaging

Signs of empyema may be visualized with a chest X-ray or chest computerized tomography (CT) scan, and sometimes an ultrasound examination may be done as well.

Thoracentesis

Though imaging studies may suggest the diagnosis, a sample of the fluid present in the pleural space is needed to confirm the diagnosis and to help select the proper treatment.

During a thoracentesis, a long thin needle is inserted through the chest wall and into the pleural space. A sample of the fluid is taken, and usually, the excess fluid is drained off. If a significant amount of fluid is present, symptoms will often improve after the fluid is drained.

The fluid obtained is sent to the lab for analysis. A culture is done to isolate the specific bacteria involved and to determine the best choice of antibiotics to treat the infection.

Treatment Options 

The treatment of an empyema entails removing the fluid and treating the underlying process.

Fluid Removal

The fluid is removed via a thoracentesis, usually in the process of diagnosing the empyema. Sometimes this is fairly simple, especially if the empyema has not been present for long. A chest tube may be placed to continue draining the fluid.

When an empyema has been present for some time, it may become loculated. This occurs when scar tissue forms and separates the fluid into separate cavities. This makes draining the fluid more difficult, and sometimes several thoracentesis punctures are needed to remove the fluid from the different compartments.

Treating the Infection

Antibiotics that target most likely causes of empyema are started immediately after the diagnosis is suspected. At the same time, diagnostic tests are performed.

Complications/Surgery

With an empyema, especially one that has been present for a while, scar tissue may build up. It may be necessary for a surgeon to remove some of the scar tissue and portions of the pleura in order to resolve the infection. This can be done either through a thoracotomy (open lung surgery) or thoracoscopic surgery (minimally invasive lung surgery) with video-assisted thoracoscopic decortication being an effective and less invasive option for many people.

A serious potential complication of empyema is sepsis—an overwhelming infection throughout the body.

Summary

An empyema is an area of infected pleural fluid surrounding the lungs. It can cause fever, shortness of breath, chest pain, and a general feeling of being sick. The most common cause is pneumonia, and other conditions, including surgery and trauma, can cause it as well. Treatment consists of fluid removal and antibiotics to treat the infection.

A Word From Verywell

If you or a loved one develop empyema, it's important for you to know that it is treatable. You should begin to notice improvement of symptoms when the fluid is drained and antibiotics are started. Full recovery can take time, and it is important to be consistent with any respiratory therapy (such as breathing exercises) that your doctor recommends as you recover.